US Patent 7506616 Dual fuel air conditioning circuit-based water heater

A fuel-fired water heater is coupled to an electrically powered air conditioning refrigerant circuit in a manner permitting water to be heated with either combustible fuel or electricity. In one embodiment a condenser piping section is externally coiled around the water heater tank, in direct thermally conductive contact therewith, and in another embodiment the condenser piping section is disposed in the interior of the tank and is coiled around the water heater flue in a laterally outwardly spaced relationship therewith. In various depicted arrangements thereof the other refrigerant circuit components are compactly supported on the water heater.